Process for preparing oxidized asphalt



Sept. 12, 1939. P. SUBKOW 2,172,821

PROCESS FOR PREPARING OXIDIZED ASPHALT Filed May 15, 1938 2 Sheets-Sheet1 5&1.

Air 6 Iapor IVENTOR. Pin-21p Subkow ATT RNEY.

rnoonss r01:

2,172,821 PATENT OFFICE PREPARING OXIDIZED ASPHALT Philip Subkow, LosAngela's, Calif assignor to Union Oil Company of California, LosAngelou,- Calii'., a corporation of California Application May 13, 1938,Serial No. 207,667

10 Claims.

sealing products, andthe like. The main objection to the asphalticproducts obtained by the processes of the prior'art" resides in the lackof uniformity in the oxidation of the oil, part of the asphaltic productobtained being over-oxidized, and another part remaining onlypartiallyand insufiiciently oxidized.

According to one of the conventional methods of producing oxidized orair-blown asphalt, air or air and steam are introduced in varyingproportions into the bottom of a cylindrical still containing a chargeof asphaltic oil, and the oil in the still is heated to a temperaturesufllciently high to obtain'the necessary oxidation reaction. Thistemperature may vary from 340 to 550 F. depending on the type of finalproduct desired and the characteristics of the primary materialemployed. Ordinarily, the'oil to be treated is initially heated to about350 F. so that the air introducedinto said, oil may produce the desiredoxidation reaction. This reaction is exothermic innature, causing agradual increase in tempera ture of the oil being treated. The optimumoxidizing temperature lies between 450 and 500 F. When the oil to betreated reaches this temperature, it is desirable to maintainthe oilwithin the optimum temperature range until the completion of theoxidation reaction. Usually, this reaction is continued for 18 to 36hours, depending upon the nature of the original stock as well as thedesired characteristics of the final asphaltic product. I The oxidationincreases the melting point and decreases the penetration and ductilityof the original stock.

Immediately following the termination of the oxidation reaction thesupply of air is discontinued, anoLthe oxidizedcharge is steam blown fora period of from 1 to 5 hours. This latter operation results intheremoval of the light oils present in the originalcharge or formedduring the oxidation reaction. The removal of these lighter'fractionsobviously raises the flash point of the oxidized asphalt, therebyimproving its q'uality.

4 It is however obvious that this method of producing air-blown asphaltcannot result in a product-of the highest grade. This is, at leastpartly, due to; the fact that the air is not brought in intimate contactwith the asphaltic oil, and that the air,'passing through the oil inlarge globules or bubbles, brings only a small percentage 01' such airinto intimate contact with the 011 (thus necessitating excessivequantities of air for the amount of oxidation required), and alsoproduces an asphalt which is partly over-oxidized and partly'insufiiciently oxidized.

Furthermore, when using the conventional methods of operation, it isdiflicult to maintain a uniform temperature .ior the charge beingtreated. Thus, the oxidizing action being exothermic in nature, theadded heat results in overheating of at least a portion of the asphalticoil to a temperature at which cracking and formation of carbonaceousmaterials occur. This renders the product more brittle and less ductileas compared with an asphalt produced under conditions whereby uniformoxidation could be effected.

tion to provide a simple, eflicient and'economical It is therefore anobject of the present invenprocess and apparatus by which petroleum oilsand/or fractions thereof may be converted into asphaltic products.

-Another object of the invention is to control the variouscharacteristics of penetration, melting point, ductility, etc. of anasphaltic product. A still further object of the reaction is to providea continuous system of oxidation of oil.

It has now been discovered that the above and other objects may berealized by thoroughly and,

repeatedly intermixlng and commingling the asphaltic oil and theoxygen-containing gas under conditions whereby the oxidation of theasphaltic oil is regulated to obtain a controlled oxidation.

It has been further discovered that the above objects may be fulfilledby providing a process and an apparatus wherein the intermingling of theoil and of the oxygen-containing gas, the rate of reaction and thetemperature and degree of oxidation are regulated and controlled withinthe desired range.

It has also been discovered that a high grade asphalt may be obtained byoxidizing the asphaltic oil in stages under such conditions that theoxidation reaction in each stage oxidizes the oil only partially.Accordingly, the asphaltic oil or a fraction thereof is heated to thereaction temperature and thoroughly commingled with air or anotheroxygen-containing gas. The oxidizing reaction is regulated so that theoil. is only partially oxidized. Thereafter, the partly oxidized oil isagain thoroughly intermixed with additional quantities of air, and thereaction is controlled so that the oil is further oxidized. The degreeof oxidation is regulated by controlling in each stage the reactiontemperature, time of reaction, as well as the proportions of oil and ofair. The above described reactions are. re-

25 of. the asphaltic oil.

40 or more jets installed between the stages.

peated until the asphaltio oil has been oxidized to the desired degree,so that the asphaltic product thus produced has the desiredcharacteristics.

It has been further found that a desired thorough commingling of theasphaltic. oil or fraction thereof with the oxygen-containing gas may beobtained by jetting said gas into the oil at the point or points whereit passes from one reaction zone or chamber to the next Succeeding one.The oil to be treated and the oxygen-containing gas may be preheated tothe incipient temperature of oxidation before their introduction intothe oxidizing zones or chambers.

Therefore, the invention resides in a continu- 1 ous process and in anapparatus for such process, wherein anasphaltic oil, or a fractionthereof, and an oxygen-containing gas, such as air, are first[separately preheated to a desired temperature, introduced into anoxidation reaction zone, and thoroughly commingled'therein by jet- :0commingled with an oxygen-containing gas and in which the oxidationreaction is controlled to oxidize the oil only partially, so that. theas phaltic oil after passing through said series of oxidation stages isfinally oxidized to the desired a degree. The invention still furtherresides in'a process and apparatus wherein the commingling of the oiland gas and the passage of the oil from stage to stage is produced byjetting the oxygen-containing gas into the oil through one According tothis phase of the invention, preheated air (or another oxygen-containinggas) is introduced into each reaction zone through a series of jetswhich latter cause the commingling 45 of the air and oil' and also forcethe mixture into the next succeeding reaction section, the unusedportion of the gas, together with any vapors developed during thereaction, being withdrawn from each reaction zone and paslsed 50 througha separator for the recovery of the vapors.- This permits the use of asingle continuously-acting tower consisting of a plurality -of reactionzones, the oxidizing gas being used both for the oxidation of the oiland, for the 66 forcing thereof into the next succeeding reaction zone.

The invention still further resides in the countercurren't passage ofthe oil to be oxidized and of the oxygen-containing gas, thereby produc-60 ing a substantially complete use of the oxygen.

According to this phase of the invention, the oil being oxidized in aplurality of oxidizing zones or stages as described hereinabove, theoxygencontaining gas from a later stage 0i oxidation 65 is utilized inpart or in whole for the purpose of commingling with'and oxidizing theasphaltic oil coming from a prior stage of oxidation. The countercurrentcontinuous operation, according to the above process, also increases thethrough- 0 put and efliciency of the apparatus, als well as the properoxidation of the primary material.

For a better understanding of the above enunciated principles of thepresent invention referonce is now made to the drawings, Fig. 1 of 75which discloses schematically an embodiment of an apparatus which may beemployed for the carrying out of the process constituting thesubject-matter of the present invention, while Fig. 2 is an enlargedview of a jetting device described more fully hereinbelow. Figure 3discloses schematically another embodiment of apparatus which may beemployed for carrying out other embodiments of the processesconstituting the subject matter of my invention.

Referring more particularly to Fig. 1, a vertical cylindrical drum I0 isdivided into a plurality of reaction zones or sections ll'a, llb, H0,lid, 6, and H1, these sections beingseparated from each other by meansof plates I2. Each of these sections is provided in its lower portionwith a coil 13 which is used for cooling the interior of the section, asby means of a cooling medium, such as water or oil, circulated throughsaid coil. However, when necessary, these coils I3 may also be used forheating the interior of the sections, in which case a heating'mediumsuch as steam, hot water or hot oil is circulated therethrough.

The uppermost section I la communicates with an oil storage tank l5 bymeans of a pipe I6 provided with a valve I'I, pump !8 and heating coilIS. The air or a similar oxygen-containing gas, ulsed for the oxidationof the oil introduced into section Ila from tank [5, enters said sectionthrough pipe 2la equipped with a plurality of open-ended nipples 22 andwith a valve 23a. The airis introduced into said pipe 2Ia from anoutside source through line 24, valve 25, heater 26, pump 21 and line28. This latter line 28 is further provided with branch lines 2|b, 2lc,2Id and 2Ie (similar to pipe 2la), which lines communicate respectivelywith the sections or chambers lib, Ilc, lid and He, said lines beingalso provided .within the sections or chambers with a plurality ofopen-ended nipples 22. These branch lines are further equipped with nextsucceeding lower nozzle. Such an arrangement permits the liquidsurrounding said injectors 30 to flow into the nozzles. Also the jettingeffect produced by the passage of air into said.

injector 30 from the above-mentioned nipples 22 causes a suction effect,thus drawing the liquid 'into the injectors through the wider portionsof the nozzles 3|. The lowermost nozzle of each injector 30 passesthrough the partition or plate i2, thus communicating adjacent reactionsections.

The uppermost reaction section I la is further provided with an air andvapor discharge line 32a provided with a valve 330. This line 32a opensinto a pipe 34 equipped with a pump 35 and condenser 36. The upperportions of the reaction zones or sections Hb, Ilc, Hd, lie and II! alsocommunicate with line 34 through lines 2227, 32c, 32d, 32e and 32f,respectively, said lines being provided with valves 33b, 33c, 33d, 33cand 331'. The opposite end of pipe 34 communicates with a separator 38,the upper end of which is in communication with the air line 24 by meansof pipe 39 provided with a valve 40. This pipe is equipped with a branchline 4|. A valved line 42 leads away from the lower portion of saidseparator.

A line 43 communicates the bottom portion of 22, said air, or a similaroxygen-containing gas,

the lowermost reaction zone I II with a line 44, one end 01' which opensinto, an asphalt storage tank 4!, while the other end opens into line Itleading from the oil storage tank 15 to the uppermost section Ha. Pipe43 is provided with a pump 40. while line 44 is equipped with valves"and 48. In operation, the asphaltic oil or a fraction thereof iswithdrawn from the storage tank l5v by means 0! pump it andiorced'through pipe.

being conveyed through pipe 24, heater 26, pump 21, line 28 and pipe Ma.The rate of introduction of such air is regulated by means oi'ppmp 21 aswell as by valve 23a in line 2hr. The rate of introduction of such airis regulated by means of pump 21 as well as by-valve 23a in line 2la.The air is passed under pressure into the injectors 30. As stated above,this passage of the air through the injectors 30 causes the oil to bedrawn into the tapered nozzles 3| ,.thus thoroughly commingling the oiland the air. The two substances being substantially at'the oxidationtem-.

. perature for the given oil, oxidation of the oil fraction occurs.However, the proportion of air to the oil, the duration of the reactionand the temperature thereof are regulated sothat only partial oxidationoccurs in the first or uppermostreaction section. A l

The thus partially oxidized oil, together with most of theairintroduced-through -line 2|a, then vpassesgto the injectors 13] into thenext succeeding reaction section 1 lb. Theair remaining in the uppermostsection Ila, as well asany vapors gen .ei'atedtherein; are withdrawnthrough line 32, 2

. The partially oxidized oil thus entering into section Ilb drops to thebottom thereof wherein it is again thoroughly commingled with additiona1quantities of. air entering into said section through branch line Zlb bythe regulation of valve 23b thereon. This air causes a further partialoxidation of the oil as well as forces it into the third reactionsection llc. As in the case of the uppermost section, the rate ofoxidation isregulated by the proportion of air to oil, by the rate ofreaction, and by the cooling of said section by means of cooling coilIS. The unused portion of the\air remaining .in'section b is withdrawntherefrom trolled by valve 33b.

introduced thereinto through lines 21c, Nd and Me and thoroughlycommingled'with the oil in the various injectors 30 disposed immediatelybelow the nipplesprojecting downwardly from said branch lines. Also theunused air is vwithdrawn from these sections through the pipes 32c, 32d,are and 32f and removed from the system-through ,line 34 by means ofpump 35. This air, as well as the vapors carried by it, may then bepassed through a condenser 36 for the condensation of theabove-mentioned vapors.

I The condensed vapors may then be segregated in separator 38 Sandwithdrawn from the system through line steaming.

through pipe 32b con- In a similar manner the partially oxidized oil lssuccessively oxidized in-sections llc, lld and lie by theoxygen-containing gas, such as air,

39 controlled by valve 40, or withdrawn from the system through branchline 4|.

The oxidized oil reaching the bottom of the lowermost reaction sectionll] is withdrawn therefrom through line 43 by means of. pump 4'.

If this product-is sufliclently oxidized, it is 0011-.

veyed: by said .pump 48 to the asphalt-storage tank 45 by opening valve48 in line 44. If, how-'- ever, the pr'oductjs considered to beinsufllcient' 'ly oxidized, it may be returned into theuppermostreaction section Ila by closing valve 48 and opening valve 41, whichprocedure would convey said product into line It. The asphaltic productthus produced and conveyed into 'tank'fimay be while hot for purposes orwithdrawn therefrom The-oxidation temperatures in the variousreaactionsections Ila, lib llf, may be main tained uniform; or mayincrease progressively from the uppermost section to the lowermostsection. Thus, if the temperature of oxidation is to be the same in allof the sections, the oil withdrawn from tank It may be heated, as.

stated above, to the incipient temperature of oxidatlon,.say 340 F., inheater I9, and then introduced into section Ila wherein it is commingledl with air introduced through pipe-Ha and which -j is alsoheated to the"same temperature. In this reaction section, the proper temperature ofoxidation is maintained by cooling cell It. The

thus partially oxidized oil then passesinto the next reaction sectionIII) wherein it is again com'mingled with preheated air and wherein" thesame temperature of oxidationas that in the uppermostreaction sectionlla is also.main tained by a cooling coil it. On the other hand,

and since the oxidation of an unoxidized oil may be carried out moreeasily than the oxidation of a partly oxidized oil, it is sometimespreferred to increase the temperature as the oxidation progresses. Insuch a case, the oil may be introduced into. the first reaction chamberor-section at a temperature-of about 340 and the re- "action temperaturein said section may be maintained by the cooling coil l3 in said sectionat about 360 F. The oil is then conveyed to section llb which ismaintained at a higher temperature, as for example 375: F. The nextsection may then be at about 400 F. Thus, thetemperatures in-the varioussections may be atgradually increasing levels until the lowermost section may beat the optimum temperature, as for example 540 F. In likemanner,-the.tempe,ratures may be controlled so as .to decrease from Hato lI-f' by regulating the-rate of cooling; In

cientiy flexible to give any variation'int p W hroughout the column Idonot intend-to limit myselfrto the numberof reaction sections or zonesshown in the drawings, ,7 but may varysaid ,number'at will. Other.musing cations may also bemade within the spirit of (my invention. Thus,instead of returningthe-L-in- .sumciently oxidized asp'haltic productfrom secjtion Hf back into the uppermost section Ha, it

may, if desired, be returned to any one of the I intermediate reactionzones Also, the air'introduced into the various reaction zones may beheated to various temperatures by the provision of heaters on the branchlines leading from pipe may be used for-steaming the asphaltic product;This. may be accomplished by closing valve 23c 28. Furthermore, the lastor lowermost section in line 2 le, and opening the valve in the steamline 49. Suchsteaming 'of the asphaltic product will s5 1 fact, theaa'ratus and the controls. are:- sum-I remove the lighter fractions andproduce asphalt of a desired flash point.

A still further modification resides in the ap-,

plication of the present'process and apparatus for the purpose offractional steam distilling of oils. When using the present process andapparatus for such steam distillation, the crude oil or a fractionthereof is continuously fed from tank I! by means of pump ll into theuppermost section Ila of the still II, steam being introduced thereintothrough branch line 2 la. Obviously the thorough commlngling of the oiland steam produces the desired distillation and evaporation of thelighter fractions, which latter are withdrawn from the system throughlines 32a and 34. The steam introduced into section Ila simultaneouslyconveys the remaining oil into the next section I lb whereinfurtherdistillation is accomplished by steam introduced through branchline 2 lb. This may be continued until the residual oil reaches thelowermost section III. Obviously the various overhead fractionsdistilled off in the different sections I Ia--I If may be eitherwithdrawn together through line 34 or may be separately conducted toindividual condensers to obtain different condensed fractions.

a vertical cylindrical drum divided into a plurality of sections IIIa,IIIb In, these sections being separated from each other by means ofimperforate plates II2. Each of these sections is provided with coils 3which may be either used for cooling the interior of the sections, as bymeans of a cooling medium such as water or oil circulated through saidcoils, or for heating purposes as by circulating steam or hot oiltherethrough.

An asphaltic oil or a fraction of the asphaltic oil to be oxidized iswithdrawn by -means of a pump Ill from a bulk storage or tank IIS, and

- is forced through line lIIi, heater 1, and line II! controlled byvalve I IS. The oil then passes into line I20 wherein it is commingledwith the oil coming from section I Ila. This oil, partially oxidized asdescribed hereinbelow, is withdrawn from section IIIa by means of a pumpI2Ia through line I22a controlled by valve Ina, said pump III a forcingthe thus withdrawn oil into the above mentioned line I20. The mixture ofpartially oxidized oil and of the fresh oil from the bulk supply II5then passes through a temperature conditioner I24a wherein thetemperature of the mixture is regulated so as to prevent overoxidationin the next oxidizing stage. The oil then passes through lines I25a andI2Ga wherein it is thoroughly commingled with an oxygen-containing gas,such as air. This oxidizing medium may consist either of fresh air orthe like introduced into line I28acontrolled by valve I29a, or of theunused portion of such oxidizing gas withdrawn by means of pump I3Ilafrom the upper part of section I I lb through line I3Ia, and forcedthrough line IlZa into the above mentioned oil mixture in line Ina.However, a mixture of the above mentioned oxygen-containing gases comingfrom both sources may be used for injection into line I2Ga. The thusobtained mixture of oil and air is then passed through line Ina,another. temperature conditioner Illa (wherein the mixture is heated tothe temperature necessary to cause the oxidation of the as phaltic oil),and then intov line I35a. This line extends into the lower portion ofsection Ila and is provided with perforations I36a through which theoil-air mixture is injected into the all contained in the lower portionof said section 1 I Ila.

' It is obvious that the passage of the oil-air mixture' through I "aand Ilia, as well as.the injection thereof through the perforations Inainto section Illa, permits a thorough contacting and .comminglingof themixture thus preventing the oil, the degree of oxidation beingcontrolled by the cooling medium passed through the coil III, as well asby the time during which the oil and air remain in the oxidizingchamber. The unused air and the vapor produced by the oxidation and bythe rise in temperature arewithdrawn from the system through. line I31controlled by valve I38. This mixture may be passed through a condenser(not shown in the drawings), for the purpose of condensing andrecovering any oil fractions entrained therein. The oil fractions thusobtained may be either returned to tank H5 or used for some otherpurpose.

By actuating valve I2'la in line Ilia and the valve in line I251), thecirculation ofthe oil partially oxidized as described above in sectionIlla (with or without any new quantities of asphaltic oil coming fromtank IIS) may be eflected through lines I156, I26b, "3b, and Iiib, andinto chamber Illb. During such passage of the partially oxidized oilfrom chamber Illa, said oil may first be commingled in the lower portionof line I251: with the oil withdrawn from section IIIb by means of pumpI2Ib through line I22b controlled by valve I23b, and forced by said pumpthrough a temperature conditioner Illb into said line I25b. The thuscommingled oil is then passed through line I28b controlled by valveIIIb, into line I331; wherein it is again thoroughly commingled with anoxygen-containing gas. As in the case of the air or gas entering intoline Ina, this oxidizing medium to be introduced into line I331) mayeither be a fresh gas entering the system through line I281), or it maybe a partly used oxygen-containing gas withdrawn from the next lowersection and introduced through line I321).

The thus obtained intimate mixture of partly oxidized asphaltic oil andan oxygen-containing gas is again either cooled or heated at Illb(depending on whether the desiredor required reaction temperature hasnot been attained or has been exceeded), and is then introduced throughline Ib and perforations I382) into the oil in the lower portion ofsection II; for further oxidation. The reaction temperature is againcontrolled by the heating or cooling coil II3 so that the desiredfurther oxidation of the oil is obtained. Also, the degree of oxidationin this section IIIb is regulated further by the period of time duringwhich the oil remains in the section. When the desired degree ofoxidation for said section has been reached, the thus partly oxidizedoil is withdrawn from the reaction zone through line I22b as describedabove, while the unused gas is removed through line I3Ia to be used forthe oxidation of the oil entering into the chamber of section Illa.

The operations of the succeeding sections are carried out in the samemanner as those of sections Illa and lllbdescribed hereinabove, Thus, byactuating the valves in lines-12Gb and I261), the partly oxidized oilwithdrawn from section IIIb may beintroduced through line Ilic into thenext succeeding section after it has been comi amass-1 ing gas or withthe unused portion of such gas coming from the second next succeedingchamber, or with gas coming from both sources.- Also this oil, beingthus introducedinto the next reaction section for further partialoxidatiom'may be first commingled with the oil withdrawn from. I

said section, as this has been described hereinabove with reference tosections Illa and lb. Furthermore, the unused portions of theoxygencontaining gas, such as air, withdrawn from the reaction sectionsmay be used for partial oxidation of the asphaltic oils being introducedinto the next preceding reaction section. g

The partly oxidized oil withdrawn, as described hereinabove, from thepenultimate section is passed into line I251: wherein it may becommingled with the partially oxidized oil withdrawn from section I n bymeans of pump IZIn through line I221: controlled by valve 311. Beforethe commingling of these two streams of oil the temperature of thepartly oxidized asphaltic body thus withdrawn from section In may beincreased or decreased by a passage through a temperature conditionerI-24n. The mixture of these two oiisis then passed into line I26ncontrolled by valve I2'ln. Inthis line the oil is thoroughly commingledwith air or an oxygen-containing gas introduced through line I28n,equipped with valve I29n. The thus obtained mixture is then conducted toline I33n, tempera 'ture conditioner I34n, and line I35n. Thereafter,the mixture passes through theperforations' I361: into the substantiallyoxidized oil in the lower portion of section I I In, Here furtheroxidation, is effected, the temperature of the reaction, as in thepreceding sections, being again controlled by cooling coil H3 and by thetime during which the oil remains in said section. I

As stated above, the oxidizing medium which has not been used up insection I I In is withdrawn from the upper portion thereof through lineIt in to be used for the oxidation of the oil passing into thepenultimate section.

If the oil in section i I In-has not been oxidized to the desireddegree, it may be recycled as described hereinabove. When the desireddegree of oxidation of the oil has been attained, the asphaltic productthus produced is withdrawn from the lower end of section In through lineI39 equipped with valve I40, and is conducted by pump Iii into anasphalt storage tank I42. The

asphaltic product thus produced may be with-.

drawn from tank I42 while hot for purposes steaming; Y

As is obvious from the above description of the apparatus and of itsoperations, the asphaltic oil or a fraction thereof may be recycledthrough any one of the above-mentioned sections a plurality of timesuntil the desired oxidation for that particular section is obtained, thethus partially oxidized oil being thus conducted to the next loweroxidizing section. Of course, if the desired partial oxidation has been,obtained in any one of the sections after the first passage of the oiltherethrough, no recirculation is necessary, and the oil can be directlyconducted successively through the remaining oxidizing sections. It isalso obvious that, instead of having superimposed reaction sections, thestructure may consist of a. plurality of separate reaction chambersinstalled on the same or different levels, and connected substantially:as described hereinabove. v

In view of the fact that the oxidation reac- -of the oxidizinggas may beintroduced into the erably to the incipient temperature of oxidation,

such temperature, as stated above, being above 340 F. and sometimesranging up to 550 F.,

depending on the charactenof the stock treated.

Thereafter, and upon the commencement of such oxidation reaction, theadditional heat generated the various temperature conditioners I2Ia,

-.I24b me, and ma. mb -1341. Such a control of the reaction temperatureprevents anover-oxidation of the oil. Also, the repeated partialoxidation of the oil, each of which oxidations isfollowed by aseparation of the un-- used oxidizing gas and then by a thoroughcommingling of the oil with additional quantities 01' such oxidizing gas(or with the unused gas coming from the next succeding oxidizingsection-i, prevents unequal oxidation of the oil,thus pro must be"controlled, as by cooling' coils H3 andducing an asphaltic producthaving the desired uniform characteristics.

The oxidation temperatures in the various re.- action sections III a,IIIb I maintained uniform, or may increase progres sively. Thus, if thetemperature of oxidation is to be the samein all sections, the oilwithdrawn from tank H5 may be heated to the incipient in, maybetemperature of oxidation, say 340" F., in heater Ill and temperatureconditioners I24a and I34a, and then introduced into section Illa afterbeing first commingled with air. In this reaction section, the propertemperature of oxidation is maintained by cooling coil H3. The partiallyoxidized oil is then withdrawn from said section, and again cooled tothe incipient temperature .in conditioners I2. and I34b beforeintroduction into the next reaction section II").

. 0n the other hand, and since the oxidation-of I unoxidized oil may becarried out more easily than the oxidationof partly oxidized oil, it issometimes preferred toincrease the temperature as the oxidationprogresses. In such a case, the

oil may be introduced into the first reaction 5 chamber at about 340 R,and the temperature in said section may be maintained at about360 F.From this reaction zone the oil may then be conveyed to section I libwhich is maintained at a.- .higher'temperature, as for example 375 F.The next section may then be at about 400 F. Thus, the temperatures inthe various sections may be at gradually increasing levels until thelast section may be at the maximum desired temperature, as for example,540 F.

- As to the air or other oxygen-containing gas to be used for theoxidation of the asphaltic oil, the total quantity of such gas necessaryfor the oxidation may be introduced into the system through line 128%,circulated'countercurrently through the system, and the unused portionwithdrawn therefrom through line' I31 together with any vapors formedduring the'oxidation reac-" tion. In the alternative, additionalquantities oil flowing to the various sections, such introduction beingmade through lines Ina, I281),

apparatus for purposes of fractional steam distillation of oils. Whenusing the present'process and apparatus for this purpose, the crude oil,or

a fraction thereof, is continuously forced from tank I I, by means ofpmnp Ill, into lines III, Ilia and Ina. In this latter, the oil isthoroughly commingled with steam. The steam, as in the case of the useof the column for oil oxidation, may come either from an outside sourceor from the next lower section I I lb. Partial distillation occurs insection Illa, the oil being conveyed from section to section for furtherdistillation. All of the steam may be introduced in which it is desiredto claim all novelty inherent in the invention.

I claim:

1. A process of blowing asphalt-producing petroleum base materials,comprising, introducing a stream of material to be treated at anelevation into a reaction chamber, separating the stream into pools,said pools having a gravity downward flow, injecting separate currentsof an oxidizing gas at selected elevations into the reaction chamber,withdrawing the residual gases from the reaction chamber, withdrawingthe oxidized petroleum base material from the reaction chamber andrecirculating at least a portion thereof through the reaction chamber.

2. A process'of blowing asphalt-producing petroleum base materialscomprising, introducing a stream of material to be treated at anelevation into a reaction chamber, separating the stream into pools,said pools having a gravity downward flow, injecting separate currentsof an oxidizing gas at selected elevations into the reaction chamber,withdrawing the residual gases from the reaction chamber, recirculatingat least a portion thereof to said chamber and withdrawing the oxidizedpetroleum base material from the reaction chamber.

3. A process of blowing asphalt-producing petroleum base materialscomprising, introducing a stream of material to be treated at anelevation into a reaction chamber, separating the stream into pools,said pools having a gravity downward flow, injecting separate currentsof an oxidizing gas at selected elevations into the reaction chamber,withdrawing the residual gases from the reaction chamber andrecirculating at least a portion thereof to said chamber, withdrawingthe with said material currents of an oxidizing gas at differentelevations with respect to the downward moving column of the materialunder .treatment, continuously withdrawing the oxidized petroleum basematerial from the reaction chamber, adjusting the heat content of atleast a por- -tion of the withdrawn oxidized petroleum base material andrecirculating it chamber.

5. In the process of claim 4, the step of adjusting the heat content ofthe, oxidized asphaltproducing material withdrawn from the reactionchamber by commingling it with fresh petroleum base-material beforereturning it to the reaction chamber.

6. A process of producing blown asphalt which comprises introducing astream of asphalt producing petroleum base material at an elevation intoa reaction chamber, causing a gravity flow of said stream in saidreaction chamber in such a manner as to separate the stream into pools,introducing for contact'with said material currents to the reaction ofan oxidizing gas at different elevations with respect to the downwardmoving column of the material under treatment, withdrawing oxidizedpetroleum base material from the reaction chamber, commingling at leasta portion thereof with fresh petroleum base material and returning the.

mixture to the reaction chamber.

7. A method for oxidizing oil which comprises commingling oil withoxygen-containing gas and introducing said mixture-into a firstoxidation stage to partially oxidize s'aidoil, withdrawing saidpartially oxidized oil from said first oxida- -tion stage, cooling saidpartially'oxidized oilto a temperature above the incipient oxidationtemperature, commingling said cooled partially oxidized oil withoxygen-containing gas, cooling said mixture to a temperature above theincipient oxidation temperature and introducing said cooled mixture intoa second oxidation stage to cause further partial oxidation of said oil,separatin unusedoxygen-containing gas'from said partially oxidized oilin said second oxidation-stage and employing said separatedoxygen-containing gas for said first mentioned commingling withoil.

8. A method for oxidizing oil which comprises commingling oil withoxygen-containing gas, introducing said mixture into a first oxidationstage to partially oxidize said oil, withdrawing said partially oxidizedoil from said first oxidation stage, commingling said withdrawn oil withoxygen-containing gas, cooling said mixture of partially oxidized oiland oxygen-containing gas to a temperature above the incipient oxidationtemperature, introducing said cooled mixture into a second oxidationstage to further oxidize said oil, separating unused oxygen-containinggas from said second oxidation stage and employing said separatedoxygen-containing gas for said first mentioned commingling with oil.

9. A method for oxidizing oil which comprises commingling oil withoxygen-containing gas, cooling said mixture to a temperature above theincipient oxidation temperature and introducing said cooled mixture intoa first oxidation stage to partially oxidizesaid oil, withdrawing saidpartially oxidized ,oil from said first oxidation stage, comminglingsaid withdrawn oil with oxygen-containing gas, coolingsaid mixture ofpartially oxidized oil and oxygen-containing gas to a temperature belowthe incipient oxidation temperature and introducing said cooled mixtureinto a second oxidation stage to further oxidize said oil, separatingunused oxygen-containing gas from said second oxidation stage andemploying said separated oxygen-containing gas for said first mentionedcommlngling'with oil.

10. A method-according to claim 9." in which said second mentionedcooling is to a higher temperature than said first mentioned cooling. j

. PHILIP SUBKOW.

